• 중소기업융합학회논문지
• /
• 제6권3호
• /
• pp.49-55
• /
• 2016

본 논문에서는 다양한 채널 환경과 요구 화질 조건에서 사용자의 QoS(Quality of Service)를 만족시키기 위한 영상 전송 방법에 대하여 제안하였다. SVC(Scalable Video Coding) 전송 기법은 비디오 신호를 중요도를 고려한 계층별 신호로 인코딩하여 전송하기 때문에, 비디오 신호 전송에 있어 효과적인 방법이다. 하지만 다양한 채널 환경에 대해서 적응적으로 다수의 사용자가 요구하는 각각의 성능을 선택적으로 만족시키는 기술에 대한 연구는 미비하다. 이에 본 논문에서는 MC-CDMA기반의 SVC 전송 시스템에서 계층 간 차등 OVSF(Orthogonal Variable Spreading Factor) 코드 할당 기법을 통해 SVC 계층 간 protection order를 보장하고 수신부로부터의 피드백을 통해 MC-CDMA의 sub-block과 각각의 계층 신호에 할당된 OVSF 길이를 조절하여 전송함으로써 다양한 채널 환경에서 각각의 사용자의 전송 환경에 따른 최적의 영상품질을 제공하는 적응 전송 시스템을 제안한다. 모의실험을 통해 제안 시스템의 성능분석을 실시한 결과 BER 성능이 향상되어 사용자의 QoS 만족이 가능함을 확인할 수 있었다.

• 한국추진공학회지
• /
• 제23권1호
• /
• pp.124-131
• /
• 2019

가스터빈엔진 고도시험설비 운용특성탐색 및 설비튜닝 연구와 유량/추력 측정방안 검증을 위한 엔진 시뮬레이션덕트 설계 연구를 수행하였다. 설비 운용특성 검증은 배압/추력 제어가 필요하므로 Spikecone type의 가변노즐을 적용하였으며, 유량검증용 ISO 쵸킹노즐의 추가장착이 가능토록 설계하였다. 시뮬레이션덕트 주유로 면적은 1D Sizing으로 결정하고, 노즐면적변화에 따른 시뮬레이션덕트 내부 유동특성은 1D/CFD 해석으로 조사하였으며, 해석결과로부터 설비운용특성 탐색 및 유량/추력 검증시험을 위한 공기공급부 시험조건을 도출하였다. Spike 노즐 구동부는 시험 전운용 구간에서 공력하중조건을 견디도록 모터, 리니어 볼스크류 등의 부품모델을 선정하였으며, 시험 시 10 mm/s의 이송속도가 가능하도록 설계하였다.

• Journal of Korea Trade
• /
• 제26권6호
• /
• pp.118-135
• /
• 2022

Purpose - The purpose of this study is to investigate the relationships among Chinese state-owned enterprises (SOEs), previous M&A experience, and the probability of deal completion in cross-border mergers and acquisitions (CBMAs). Since Chinese SOEs tend to be recognized by host countries as agents of their home country government, this study argues that SOEs will face difficulties in completing CBMA deals. However, the study expects that these difficulties may vary depending on whether the firm has previous M&A experience because firms can gain the knowledge and capabilities necessary to implement subsequent M&As successfully from past M&A experience. Design/methodology - To investigate our argument, we conduct a logistic regression using a sample of 363 CBMA deals from 304 Chinese publicly listed firms during 2007 to 2017. We used SOEs as an independent variable, experience of domestic and foreign M&As as moderating variables, respectively, and CBMA deal completion as the dependent variable. Findings - The study shows a negative and significant relationship between Chinese SOEs and the completion likelihood of CBMA deals. We find that this negative relationship is strengthened when the firm had prior domestic M&A experience, whereas foreign M&A experience alleviated the negative relationship. Originality/value - The issue of government ownership has remained unclear since government intervention has both advantages and disadvantages in pursuing CBMAs. Our findings support literature that argues Chinese SOEs face legitimacy concerns in the host countries, thereby lowering their CBMA deal completion likelihood. Furthermore, the study enriches the literature by identifying different moderating effects of domestic and foreign M&A experience on the negative relationship between SOEs and CBMA deal completion.

• Asian-Australasian Journal of Animal Sciences
• /
• 제12권5호
• /
• pp.783-787
• /
• 1999

To study the effects of different extrusion conditions of barley on growth performance, nutrient digestibility and nutrient excretion in feces, a total of 150 growing pigs ($Landrace{\times}Duroc{\times}Large$ White; average 24.4 kg body weight) were allotted to five treatments, in a completely randomized block design. The experimental diets were based on corn-soybean and 30% of barley was included in each diet; barley was the only extruded ingredient. The treatments were 1) no extrusion (Control); 2) extrusion at $100^{\circ}C$ without preconditioning (ENLT); 3) extrusion at $150^{\circ}C$ without preconditioning (ENHT); 4) extrusion at $100^{\circ}C$ with preconditioning (ECLT); 5) extrusion at $150^{\circ}C$ with preconditioning (ECHT). Temperature in the barrel was controlled within ${\pm}5^{\circ}C$ by feed rate with the addition of water at the rate of $3{\ell}\;per\;min$. in the extruder for each treatment. For the 6 week experimental period, extrusion of barley improved the average daily gain (ADG) and digestibilities of dry matter, crude protein and gross energy in growing pigs. As compared to control, significant improvements in ADG (p<0.05) were shown in the groups of feeding extruded barley at high temperature (ENHT and ECHT). There were also significant differences in the digestibilities of DM, CP and P between extrusion temperatures. Barley extruded at high temperature gave better digestibilities of DM, CP and GE than barley extruded at low temperature. Extruded barley diet groups showed significantly (p<0.05) lower excretions of DM, nitrogen (N) and P per kg gain as compared to the ground barley group. DM, N and P excretion per kg gain were also significantly lower in pigs fed barley extruded at $150^{\circ}C$ than at $100^{\circ}C$. In conclusion, extrusion considerably improved the nutritive value of barley and it appeared that temperature is the most important variable.

• Asian-Australasian Journal of Animal Sciences
• /
• 제28권11호
• /
• pp.1614-1623
• /
• 2015

The objectives of the current experiment were to study the response of the growth performance of early finishing gilts to different net energy (NE) concentrations in diets, and to compare the NE values of diets between calculated NE values and measured NE values using French and Dutch CVB (Centraal Veevoederbureau; Central Bureau for Livestock Feeding) NE systems. In a metabolism trail, the NE concentrations in five diets used for the growth trial were determined based on digestible nutrient concentrations, digestible energy, and metabolizable energy using a replicated $5{\times}5$ Latin square design with 10 barrows (initial body weight [BW], $39.2{\pm}2.2kg$). In a growth trial, a total of 60 early finishing gilts (Landrace${\times}$Yorkshire; initial BW, $47.7{\pm}3.5kg$) were allotted to five dietary treatments of 8.0, 9.0, 10.0, 11.0, and 12.0 MJ NE/kg (calculated, as-is basis) with 12 replicate pens and one pig per pen in a 42-d feeding experiment. The NE and amino acid (AA) concentrations in all diets were calculated based on the values from NRC (2012). Ratios between standardized ileal digestible AA and NE concentrations in all diets were closely maintained. Pigs were allowed ad libitum access to feed and water. Results indicated that calculated NE concentrations in diets (i.e., five dietary treatments) were close to measured NE concentrations using French NE system in diets. The final BW was increased (linear and quadratic, p<0.05) with increasing NE concentrations in diets. Furthermore, average daily gain (ADG) was increased (linear and quadratic, p<0.01) with increasing NE concentrations in diets. There was a quadratic relationship (p<0.01) between average daily feed intake and NE concentrations in diets. Feed efficiency (G:F) was also increased (linear, p<0.01) as NE concentrations in diets were increased. The NE intake per BW gain (kcal NE/kg of BWG) was increased (linear, p<0.01) with increasing NE concentrations in diets that were predicted from both French and Dutch CVB NE systems. Linear regression indicated that predictability of daily NE intake from the BW of pigs was very low for both French ($R^2$, 0.366) and Dutch CVB ($R^2$, 0.374) NE systems. In conclusion, increasing NE concentrations in diets increase BW, ADG, G:F, and NE intake per BW gain of early finishing gilts. The BW of early finishing gilts is not a good sole variable for the prediction of daily NE intake.

• 한국위성정보통신학회논문지
• /
• 제5권1호
• /
• pp.58-62
• /
• 2010

본 논문에서는 갈릴레오 수신기 구조의 요구사항을 검토한 후 시뮬레이션을 통해 RF 성능 파라미터들이 갈릴레오 수신기 성능에 어떠한 영향을 주는지 알아보았다. 먼저 갈릴레오 시스템의 일반사항과 갈릴레오 수신기의 구조 및 특성에 대해 고찰하였고, 갈릴레오 수신기의 성능 분석을 위해 에질런트사의 ADS(Advanced Design System)를 이용하여 15 % EVM에 상응하는 16 dB C/N의 갈릴레오 수신기 성능 요구 규격에 초점을 맞춰 갈릴레오 수신기를 설계하였다. AGC(Automatic Gain Control) 동작을 확인하기 위해 수신 파워에 따른 출력 IF의 변화량을 확인하였으며, 일정한 IF 출력을 통해 정상적인 AGC 동작을 확인하였다. 수신기 입력 파워에 의한 성능 분석과 수신기 국부 발진기의 위상 잡음 변경에 따른 성능 열화 분석을 통해 -127 dBm의 입력 파워에서 EVM(Error Vector Magnitude) 변화를 알아보았다. 또한 AGC의 이득 범위(-2.5 dB ~ +42.5 dB)에 의해 결정된 -92 dBm ~ -139 dBm의 입력 파워에서 ADC(Analog to Digital Converter)의 비트 변경에 따른 성능 분석을 하였으며, LO의 위상 잡음이 감소하고 ADC의 비트가 증가함에 따라 EVM이 향상 됨을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권6호
• /
• pp.800-807
• /
• 2019

Objective: The aim was to evaluate backgrounding beef steers on oat + ryegrass pastures mixed with vetch and/or using energy supplementation. Methods: A randomized block design with three treatments and three replications was used. The treatments were: grass + supplement (oat + ryegrass + supplementation), legume + supplement (oat + ryegrass + vetch + supplementation) and grass + legume (oat + ryegrass + vetch). A continuous grazing system with a variable stocking rate was used. Twenty-seven intact crossbred steers (1/4 Marchigiana, 1/4 Aberdeen Angus and 2/4 Nellore) aged 7 months old and average weight of 190 kg were used. Steers were supplemented at 1% of the body weight of ground corn. The experiment lasted 84 days, between May and August 2014. Behavioral assessments were performed two times per experimental period, for 24 hours. Results: The forage mass was different between treatments, being greater for steers fed without legume. The accumulation rate, forage allowance, and stocking rate did not differ between treatments due to the adequate adjustment of forage allowance. The final weight of animals, as well as the dry matter intake (kg/d), did not differ between treatments. However, forage intake was higher for non-supplemented animals in relation to supplemented steers. Supplement intake did not alter the total digestible nutrient intake due to pasture quality. Animals fed grass + supplement had higher live weight gain per area than those fed grass + legume. Animals without supplementation spent more time in grazing. Conclusion: Feeding behavior was not altered by mixing with vetch or supplementation. Non-supplemented animals started the grazing peak earlier and spent more time in grazing than those supplemented; however, the average daily gain was similar between treatments. The live weight gain per hectare was 47% higher in pastures in which the animals received supplementation compared with those mixed with vetch, a consequence of the substitutive effect.

• 한국통신학회논문지
• /
• 제30권4C호
• /
• pp.269-275
• /
• 2005

본 논문에서는 움직임이 작은 동영상에 효과적인 새로운 움직임 벡터 부호화 알고리듬을 제안한다. 제안 알고리듬에서는 새롭게 정의된 파라메타를 이용하여 동영상의 움직임 정도를 추정한다. 그리고 움직임이 작은 경우에 움직임 벡터차는 기존 부호어들로부터 생성되는 단일 결합 부호어에 의하여 압축된다. 모의 실험 결과는 움직임이 작은 동영상에 대하여 제안 알고리듬이 기존 방식들에 비하여 평균 $15\%$정도의 성능 향상을 보였다. 또한 제안 알고리듬은 새로운 통계치의 계산이나 부가적인 메모리 사용이 요구되지 않는 장점을 지닌다.

• 융합신호처리학회논문지
• /
• 제6권2호
• /
• pp.89-94
• /
• 2005

본 논문에서는 새로운 방법의 Fuzzy PID 제어기를 제안한다. 우선 절대형 디지털 PID 제어기에서 두 가지 문제점이 있다. 첫째는 매 제어 주기마다 많은 데이터의 합을 구해야 하므로 계산시간이 많이 소요되고, 둘째는 이 계산을 위해 이전의 모든 데이터를 보관하고 있어야 되기 때문에 메모리가 많이 필요한 문제점이 있다. 위의 문제점을 개선하기 위해 속도형 디지털 PID 제어기를 사용한다. 제안한 제어기에서는 PID 제어기의 목표 값과 현재 출력 값의 차인 크리스퍼(crisp) 출력 오차를 그대로 사용하지 않고 퍼지추론의 단계는 가지면서 Rule Table은 갖지 않는 특징이 있으며 출력 소속 함수에 두 변수의 관계와 범위에 의해 도식화된 영역에서 삼각형 무게 중심법으로 비퍼지화된 비선형 출력 값을 PID 계수에 인가하는 새로운 Fuzzy PID 제어기를 제안한다.

• 대한수의학회지
• /
• 제51권4호
• /
• pp.309-313
• /
• 2011

Dogs are considered to be the best companions of human beings due to their loyalty, obedience and pleasant disposition. Jejunum is the largest part of small intestine mainly involved in absorption of nutrients. Jejunal resection up to 80% allows normal weight gain while resection up to 90% increased morbidity and mortality. In the present study, 20 dogs were divided into 4 groups based on the degree of jejunal resection i.e. A (70% resection), B (80% resection) and C (100% resection) while group D served as control. Dogs in the 70% and 80% jejunal resection group showed normal growth and function while 100% jejunal resection resulted in weight loss and alteration of hematological and biochemical parameters.